This laboratory will be sent fresh solid tumor specimens which they will then disaggregate and incubate under appropriate growth conditions. The laboratory personnel will then make slides from mitotically active cultures. When metaphases have been identified under the microscope, the chromosomes in them will be stained by suitable methods (primarily with Wright's stain, giemsatrypsin or quinacrine) and the individual cells will be analyzed to determine the karyotype. Photographs will be taken of good metaphase spreads, and the chromosomes in them will be studied in detail. The goal of the contract is to identify changes in chromosome number and/or structure that may be important in the etiology of specific types of solid tumors.